The disclosure relates generally to acoustic inspection, and more particularly, to an acoustic data collection system and method using an unmanned aerial vehicle that is advantageous for acoustic inspection of, for example, an industrial machine.
Acoustic inspection of industrial machines is oftentimes required to be performed on a regular basis to ensure compliance with environmental, health and safety (EHS) regulations, and to keep the machines operating reliably and effectively. Illustrative large industrial machines that require inspection may include but are not limited to: any variety of power plant regardless of power source, gas turbines, steam turbines, generators, compressors, wind turbines, manufacturing equipment like industrial presses and printers, etc. In order to inspect such large industrial machines, unmanned aerial vehicles (UAVs) equipped with a variety of non-destructive evaluation devices may be employed. The non-destructive evaluation devices may include, for example, a visual camera, an infrared camera, an acoustic transmitter, an acoustic receiver, a radiation source, a radiation detector, etc.
Use of UAVs to inspect machines has been found advantageous because the size of some machines makes inspection difficult, requiring use of large lifts/cranes and/or construction of scaffolding to provide access for close inspection of the various components. A technician can oftentimes manually climb the relevant parts of the machine, e.g., using climbing equipment, stairs/catwalks, etc., but this is a time consuming, labor intensive and hazardous activity. In addition, there are often limits placed on the number of climbs any one technician can perform per day. This issue can be particularly problematic when an industrial machine has a large number of parts requiring inspection, e.g., a multi-unit combined cycle power plant or a wind turbine farm, or is spread across a large geographic area. In some instances, the industrial machine must be shut down when personnel are in close proximity, which reduces the production capability of the industrial machine currently undergoing an inspection. Inspection of industrial machines in certain geographic locations may also be challenging. For example, inspections of industrial machines may require testing at a position over water, or at a position on land that is impossible or difficult to access using ground-based vehicles.
Acoustic data is one parameter that is regularly inspected with certain industrial machines, typically to ensure compliance with EHS regulations, such as those that limit noise or vibrations. Acoustic data is also collected to identify areas in need of repair. In many settings, acoustic data is acquired by a human operator manually carrying an acoustic receiver to desired locations, or perhaps by installing a very expensive semi-permanent array of microphones at desired locations. While UAVs have been provided with acoustic receivers to collect acoustic data, current UAV acoustic data collection systems collect raw data in a haphazard manner. For example, the UAV may collect acoustic data while flying about performing other inspections or while performing a repair. Consequently, the raw acoustic data collected may not be of much use for acoustic analysis because it contains unnecessary sounds of, for example, a repair tool on the UAV, the UAV propulsion system, etc. Further, if the acoustic data is not collected with any meaningful identification of location relative to the industrial machine, it can make identification of the source of the acoustics impossible.